HDU 3746 Cyclic Nacklace KMP

题目地址：http://acm.hdu.edu.cn/showproblem.php?pid=3746

KMP算法——

AC代码：

 

#include <iostream>

#include <cstdio>

#include <cstdlib>

#include <cmath>

#include <cstring>

#include <string>

#include <vector>

#include <list>

#include <deque>

#include <queue>

#include <iterator>

#include <stack>

#include <map>

#include <set>

#include <algorithm>

#include <cctype>

using namespace std;



typedef long long LL;

const int N=200005;

const LL II=100000000;

const int INF=0x3f3f3f3f;

const double PI=acos(-1.0);



int next[N],len,nextval[N];

char str[N];



void getnext(char *p)

{

    int j=0,k=-1;

    next[0]=-1;

    while(j<len)//len是p的长度

    {

        if(k==-1||p[j]==p[k])

        {

            j++;    k++;

            next[j]=k;

        }

        else

            k=next[k];

    }

}



void getnextval(const char *p)

{

    int i = 0,j =-1;

    nextval[0]=-1;

    while(i!=len)

    {

        if(j==-1||p[i]==p[j])

        {

            ++i;++j;

            if(p[i]!=p[j])

                nextval[i]=j;

            else

                nextval[i]=nextval[j];

        }

        else

            j=nextval[j];

    }

}



int main()

{

    int i,j,T;

    cin>>T;

    while(T--)

    {

        scanf("%s",str);

        len=strlen(str);

        getnext(str);

        int min_repeat=len-next[len];

        if(min_repeat==len)

            printf("%d\n",len);

        else if(len%min_repeat==0)

            printf("0\n");

        else

            printf("%d\n",min_repeat-len%min_repeat);

    }

    return 0;

}